Smoke cord

ABSTRACT

A smoke and fume producing device is provided in the form of a continuous elongated cord. The cord consists of a central igniter stem surrounded by the main pyrotechnic smoke charge and suitable outer coverings. The smoke charge preferably consists of a mixture of zinc oxide, a perchlorate oxidizer and a plasticized polyvinyl chloride resin and burns without flaming at a temperature of about 500*C.

0 United States Patent 1 [111 3,881,420 Smith et al. 1 May 6, 1975 [54] SMOKE CORD 2,939,779 6/1960 Brock 149/84 7 62 l 149 76 [751 Inventors: John Mitchell Smith Simsbury; 2 223 223 2/867 re tf et a1 102/27 Hector Joseph Zilwsky, Litchfield, 3,467,558 9/1969 Wernette..... 149/76 both of Conn. 3,724,382 4/1973 Zilcosky 102/90 [73] Assignee: The Ensign-Bickford Company,

Simsbury, Conn. Primary Examiner-Verlin R. Pendegrass [22] Filed: July 13, 1973 Attorney, Agent, or Fzrm-Prutzman, Hayes, Kalb &

Chilton [21] Appl. No.: 379,175

Related US. Application Data 57] ABSTRACT [63] Continuation-impart of Ser. No 183,164, Sept, 23,

1971, abandoned. A smoke and fume producing device is provided in the form of a continuous elongated cord. The cord con- [52] US. Cl. 102/90; 102/27 R sists of a central igniter stem surrounded by the main [51] Int. Cl C061! 3/00 pyrotechnic moke charge and suitable outer ove [58] Field of Search 102/29, 90; 149/15, 76, ings. The smoke charge preferably consists of a mix- 149/84 ture of zinc oxide, a perchlorate oxidizer and a plasticized polyvinyl chloride resin and burns without flam- [56] References Cited ing at a temperature of about 500 C.

UNITED STATES PATENTS Cl 2 D n 2,923,239 2/1960 Andrew et al. 102 27 8 gums SMOKE CORD RELATED APPLICATION This is a continuation in part of our co-pending application, Ser. No. 183,164, filed Sept. 23, 1971 and entitled Smoke Cord and now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates generally to a device for generating smoke, fumes or similar vaporous substances such as tear gas, insecticides, cloud nucleants and the like. More particularly, it is concerned with a new and improved fume dispensing device of wide application having a unique structural configuration and improved operating characteristics.

Fume generating devices have been used effectively heretofore for both civilian and military applications. Generally such devices include compact relatively inflexible containers, such as metal canisters, grenades and similar structures, capable of operatively deploying or dispensing smoke, fumes or gas within a desired area. Usually the smoke and/or gas canisters are pyrotechnically actuated, produce a limited volume of fumes per time unit of operation and only localized dissemination of the agent being dispersed due to the point source of the smoke. This limited and localized generation of smoke and gas is partially due to the structural configuration of the housing or container and partially due to the design and type of fume producing charge contained therein.

Typically the device takes the form of a relatively small metal canister or similar solid housing which remains substantially intact during discharge of its pyrotechnic payload. The canister can become quite hot as a result of the pyrotechnic discharge of its contents and thus can constitute a safety hazard to the unsuspecting. The fume producing agent carried by the container is usually compressably confined within the solid container and upon ignition burns at a relatively high combustion temperature, that is, at a temperature of about 1,000C. Although the pyrotechnic compositions conventionally employed in tear gas grenades and the like will flame when burned unconfined and thereby destroy part of the fume producing agent prior to its dissemination, flaming is generally suppressed by the pres sure buildup in the confining canister. However, even though the composition does not flame, its high com bustion temperatures necessarily result in destruction of a portion of the agent being dispersed and consequently result in low operating efficiency.

These low efficiency, low output rate canisters have the additional inherent disadvantage of being solid objects that can be easily picked up during their operation and thrown back to their point of origin. Further, after all the agent has been dispensed, the spent housing can be used in a manner contrary to its originally intended purpose.

Accordingly, it is a primary object of the present invention to provide a new and improved device for disseminating fume product agents such as tear gas, smoke, insecticides, cloud nucleants and the like in a highly efficient manner while obviating many of the disadvantages heretofore experienced with canister-type devices.

Another object of the present invention is to provide a new and improved fume producing device having a structure capable of rapidly disseminating its payload in a highly efficient manner while eliminating those residual container components capable of being picked up and thrown back to their point of origin.

Still another object of the present invention is to provide a new and improved fume generating device of continuous flexible cord-like configuration capable of being rapidly deployed so as to operatively cover large areas even at remote locations. Included in this object is the provision for rapid generation of an elongated Wall of fumes having any desired configuration.

An additional object of the present invention is to provide a fume generating device of the type described capable of delivering the dispersible agent at a rate controlled to suite the end use desire. Included in this object is not only control over the linear burning rate of a pyrotechnic cord but also substantially improved fume volume output per unit of time at the particular linear burning rate employed.

A further object of the present invention is to provide a flexible, fume generating pyrotechnic cord of the type described which upon ignition not only provides rapid and efficient dissemination of the generated fumes but also provides flameless, relatively unconfined burning of the fume generating material coupled with safe handling and substantial disintegration of the container thereby preventing subsequent use thereof contrary to its intended purpose.

Still another object of the present invention is to provide a smoke-generating device of cordlike construction having an extended length relative to its cross section and adapted to be coiled, spliced and the like. The cord contains a smoke-generating agent having a relatively low burning temperature and is characterized by flameless combustion at atmospheric pressure.

Other objects will be in part obvious and in part pointed out in more detail hereinafter.

These and other objects are accomplished in accordance with the present invention by providing a flameless pyrotechnic fume generating device substantially different in configuration and operation from the canisters used heretofore. The device is of a cordlike configuration and comprised of a pyrotechnic igniter stem, a fume-generating pyrotechnic charge having a burning temperature well below 1,000C in continuous abutting relationship with the igniter along its length and an outer covering confining the charge yet capable of rapidly releasing the fumes or gas generated by the charge upon ignition of the charge by the igniter.

A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and the accompanying drawings which sets forth certain illustrative embodiments and is indicative of the various ways of which the principles of the present invention are employed.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawing:

FIG. 1 is a perspective view, partially broken away and partially in section, of a fume-producing device of the present invention; and

FIG. 2 is an enlarged end view of the cord of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing in greater detail wherein like reference numerals indicate like parts in both figures, a fume producing device embodying the principles of the present invention is shown in the form of an elongated flexible cord, designated generally by the numeral 10. The cord is shown in the drawing as consisting of an elongated central igniter thread or stem 12 circumscribably confined by a primary charge 14 of fume producing pyrotechnic material and encased within a suitable covering 16.

The central igniter 12 extends along the length of the cord 10 and in the preferred embodiment of at least partially controls the longitudinal burning rate of the smoke producing charge 14. As will be appreciated, the igniter may extend peripherally along the cord and may be of substantially shorter length than the cord. However, in accordance with the illustrated embodiment, the igniter 12 is in the form of an elongated thread which extends along the entire length of the smoke cord 10 at its core.

In order to provide a reliable ignition function throughout the entire length of the cord, the center thread 12 preferably incorporates a pyrotechnic or incendiary material capable of providing a concentrated burning zone which continuously progresses along the length of the cord. The preferred pyrotechnic and incendiary ignition materials in the stem 12 are inorganic mixtures such as the well-known metallic powder and metal oxide compositions conventionally employed as igniter mixtures in various pyrotechnic devices. However, other suitable linear igniters such as low energy detonating cord on the like may be effectively employed either alone or in admixture with pyrotechnic igniters. In this connection, it has been found that consistently good results are obtained either from a wirebound flexible cord containing a core of thermit such as the incendiary igniter sold under the trademark lgnitacord by the Ensign-Bickford Company of Simsbury, Connecticut or from a soft flexible yam-wound incendiary igniter sold under the trademark Quarrycord by the same company. Both products are cordlike in appearance and burn progressively along their lengths with an external flame at the zone of burning which is generally short and quite hot.

As mentioned, the differences in the burning rates of these igniters offers a means for controlling the burning rate of the smoke cord. The wirebound flexible cord, commonly referred to as continuous hot wire lighter, is commercially available in at least two burning speeds, namely, one of approximately 0.05 0.06 feet per second and the other at about twice that speed, that is approximately O.1O 0. 12 feet per second. However, as will be appreciated, the use of such igniters as the center thread of the smoke cord will leave a small wire coil as a solid residue after combustion is complete. Where such a residue is undesirable or where an increased buming rate is beneficial, the yarn covered, soft, flexible incendiary cord, such as the Quarrycord igniter, may be advantageously employed. Due to the absence of the metal covering, the yarn wound igniter stem is immune from premature ignition by stray or static electrical charges and thereby provides increased safety coupled with flexibility and reliability.

For further clarity and ease of understanding the yarn wound igniter center thread 12 is illustrated in detail in FIG. 2 of the drawings as consisting essentially of coated strands of cotton incased within a suitable covering consisting of a thin plastic tape 22 crosswound with yarns 24 and coated with a suitable finishing layer 26 to an approximate diameter of about 0.1 inch.

Although such yarn would center thread of type igniters normally burn with a vigorous external flame at a rate of about 1 to 2 feet per second, it has been found that the burning rate of smoke cords using such igniters is substantially faster. The burning rate of smoke cords using Quarrycord igniter is about ten times faster than the normal burning rate of the igniter, that is, approximately 20 feet per second. Thus, as will be appreciated, the actual ignition rate of the smoke cord is a function of both the burning rate and type of center igniter utilized, particularly since the granular smoke producing mixture 14 does not itself readily propagate in a linear fashion along the cord. In this way the burning rate of the smoke cord can be controlled by judicious selection of the igniter stem 12.

The main or smoke producing charge 14 of the cord 10 is a combustible pyrotechnic mixture capable of being ignited by the center thread and of undergoing a burning process in a flameless manner at a relatively low temperature, that is, at a temperture of about 350 500C. Advantageously such a composition provides full and complete utilization of its smoke producing properties without destroying or substantially reducing the quantity of fumes being dispersed. The flameless nature of this powdered pyrotechnic persists regardless of whether the material is confined or unconfined and over a wide density range of about 0.1 2.5 grams per cubic centimeter. This is accomplished in accordance with the present invention by utilizing a composition substantially free of the hexachlorethane heretofore conventionally employed in white smoke mixtures of this general type. Instead, the composition of the present invention utilizes a halogen-containing polymeric resin fuel of the plasticized vinyl type together with an inorganic oxidizer such as a perchlorate salt and the conventionally employed zinc oxide. The plasticized halogenated resin functions not only as a combustible organic fuel and source of halogen for reaction with the zinc oxide but also serves as a binder for the pyrotechnic composition.

Advantageously the organic plasticizer used in conjunction with the halogen containing resin acts as a vehicle for mixing and homogenizing the components of the formulation while obviating solvents in the system. The plasticizer may be of the general purpose type suited for use with halogen containing polymers such as polyvinyl chloride. The preferred plasticizers are generally esters of dibasic acids such a phthalic, adipic, maleic, succinic or the like. For example plasticizers such as dibutyl and dioctyl phthalate, dihexyl sebacate, dilauryl adipate and the like may be used. These liquid plasticizers, being fully compatible with the resin and of low volatility, become an integral part of the plastisol composition that serves as a dispersing medium for the zinc oxide and perchlorate oxidizer as well as a fuel, binder and halogen donor.

The resins found most suited to accomplishing the flame suppressing and low combustion temperature objectives of the present invention are the high molecular weight polymers and copolymers having a moderate to high halogen content, such a vinyl chloride and copolymers thereof. In this connection, the vinyl resins sold by B. F. Goodrich under the trademark Geon such as Geon 121 have given good results. These polymers are high molecular weight homopolymers of vinyl chloride having an average molecular weight of about 200,000. The solid particulate resin has a specific gravity of about 1.4 and an inherent viscosity of about 1.2 as measured by test procedures ASTM-D-l234-60-A. The preferred material, polyvinyl chloride, has a chlorine content of about 56 percent but other polymers and copolymers of moderate to high halogen content such as vinylidene chloride may also be employed.

The polymeric resin as received from the supplier is a fine powder having a bulk density of about 20-25 lbs/cubic foot and a particle size small enough so that 100 percent of the powder easily passes through a 200 mesh screen. The resin is preferably of the stir-in type and is preferably plasticized with a general purpose plasticizer of the less volatile type, such as dioctyl phthalate, using substantially equal proportions of the resin and plasticizer. However, frequently it is desired to reduce the relative amount of plasticizer to achieve proper processing conditions.

Excellent results are achieved when substantially equal proportions of the plasticized halogenated resin, oxidizer and zinc oxide are utilized. However, variations in the amounts of the respective components are permissible. Accordingly, the plasticized resin may broadly vary from about percent by weight up to about 60 percent by weight and the amount of zinc oxide may be from about to about 40 percent of the pyrotechnic composition. Surprisingly, formulations using less than 15 percent of zinc oxide tend to flame while zinc oxide concentrations below about 2 percent are ineffective. It is also preferred in accordance with the present invention to incorporate into the smoke composition a minor amount of an additional halide donor, such as ammonium chloride, particularly at medium or low resin concentration levels. Thus, it has been found that the operable compositions generally fall within the approximate ranges given in Table I.

In preparing the white smoke formulation for use in the cord of the present invention, the various components can be mixed in a convenient manner so as to obtain homogeneity of the components. Thus, the polyvinyl chloride resin is mixed with an equal amount of plasticizer to form a suspension to which is added the zinc oxide, ammonium perchlorate and ammonium chloride. The components are blended in a suitable mixing container to provide the requisite distribution of the components throughout the composition. For safety considerations it is generally preferred that the oxidizer be the last component to be added to the mix. The resultant pastelike mix is spread on trays to facilitate deaeration and permit the resin to solidify. The solid cake is then granulated and preferably fractionated to provide particles of a size that will pass through a mesh screen and be retained on a 60 mesh screen. These particles, which are not sensitive to ignition upon impact, are thereafter utilized to form the primary charge 14 in the smoke cord of the present invention. It will be appreciated that the pastelike mix could also be cast in its final shape or extruded about the central igniter if desired.

Where the cord is to be utilized for purposes other than merely the production of smoke, such as where the cord is to contain tear gas producing material and is to be used for riot control or the like, or is to contain insecticides, fire extinguishing agents or other materials to be disseminated, the granular white smoke mixture is admixed with the agent prior to fabrication of the cord. Among such tear gas producing riot control agents are the ortho substituted benzal malononitriles such as fluro, chloro, nitro, cyano, or hydroxy substituted malononitriles. It has been found that exceptionally good results are obtained when the mixture contains about 20 to 50 percent of the riot control agent. In the preferred formulation the riot control agent constitutes about 35 parts by weight of the smoke producing charge 14. Insecticides such as malathion, pyrethrum or the like or cloud nuicleants such as silver iodate as well as smoke coloring dyes may also be incorporated with good results.

As mentioned hereinbefore, the pyrotechnic smoke producing mixture 14 encases the central igniter l2 and is itself confined by a suitable longitudinally wrapped tape 30 such as a paper or polyethylene tape over which is applied a dual wrapping or rayon yarns 32. Although varying amounts of the smoke producing mixture may be employed in the main charge 14 depending on size of the igniter and the desired flexibility of the cord, it has been found that best smoke volume is achieved when the main charge 14 comprises about 10 to 20 grams per foot. Such cords will generally have a diameter of about 0.3 0.4 inch after the yarn wrappings have been applied although even cords of low smoke volume have been produced and operated successfully. For example, cords having an igniter thread of 0.1 inch in diameter circumscribed by a smoke producing mixture of the type described and confined by plastic tape and yarn so as to provide an effective outside diameter of only 0.15 inch have proved operative. However, as mentioned, the smoke volume from such a cord is low due to the large area occupied by the center igniter.

The smoke cords are elongated flexible members that can be readily coiled on a spool for dispensing and have a large length to diameter ratio, i.e. a ratio substantially in excess of 50:1. Preferably the cord is of continuous length but practically is sold in spool lengths of 250 feet and used in lengths of at least about 10 feet and more. Shorter lengths containing insecticide can be coiled about trees or merely coiled in one spot to provide a point source of smoke either on the surface or underground. Thus, the configurational opportunities for the cord are varied and versatile.

It is also an advantageous feature of the present invention that the cord 10 includes an outer plastic sheath 34 not only to provide waterproofing for underwater use and improved structural integrity but also to surprisingly provide increased smoke volume. This latter effect is apparently due to more complete combustion of the pyrotechnic material as a result of the improved confinement provided by the flexible plastic sheath.

As will be appreciated, the flexible cord of the present invention may be utilized in the form of long lengths propelled to their desired location and ignited to produce a solid and continuous wall of smoke and/or gas. Additionally, elongated pieces of cord may be spliced by knotting either the cord itself or merely the center igniter thereof. In either case, there is no interruption in ignition between the joined cords although a slight ignition hesitation, generally of the order of 8 to 10 seconds, will occur when the cords are merely knitted together as opposed to the fraction of a second hesitation when knots are provided in the center thread.

The cord of the present invention usually generates a linear wall of smoke or gas at a rate of approximately 20 feet per second with high volume output in a short period of time. It can be rapidly launched by a suitable rocket propelled device and used to mark or outline large areas or provide. linear type signals for aircraft or the like. Additionally, the fume generating cord of the present invention can be laid out by hand and used for riot control or it can be placed in rows in an orchard for insect control or frost damage prevention. Since the total radial burning time for a smoke cord having a core load of about 10 to 12 grams per foot is only 6 seconds, the payload is delivered within a fraction of the time previously required by tear gas grenades and similar canister-type devices. For example, the payload delivered by the cord in only 6 seconds would require 30-60 seconds of delivery time by a gas grenade. The rapid rate of smoke generation essentially eliminates the possibility of the device being picked up and thrown back to its point of orgin and further eliminates the hazard of solid containers which might subsequently be utilized in a manner adverse to their original purpose. As mentioned, the rate of burning can be controlled to suit the use desired and may be substantially slower for insecticidal application or fast for dispensing fire extinguishing agents or for use as a linear flare.

The invention will be further described with reference to the following specific examples which are provided in order that the present invention may be more readily understood. These examples are given by way of illustration only and are not intended to be a limit on the practice of the invention.

EXAMPLE 1 A granular smoke formulation was prepared from 15 parts by weight of a polyvinyl chloride resin (Geon 121),15 parts by weight of dioctyl phthalate plastic ize r, 27 parts by weight of ammonium perchlorate, 35 parts by weight of zinc oxide and 8 parts by weight of ammonium chloride. The granular smoke formulation had a particle size which passed through a mesh screen and retained on a 60 mesh screen. Using a thermalite lgnitacord Type C having a burn rate of 7-10 sec/ft as the center stem, a continuous smoke cord was fabricated from the aforementioned formulation at a core load of l 1.8 grams per foot. Plastic tape of 1.2 mill thickness was wound about the particulate smoke formulation and countering rayon yarns were applied thereto, resulting in a cord having a gross weight of 14.8 grams per foot and an average diameter of 0.27 inch. I

Upon ignition of the center thread, the cord exhibited a burning rate of 0.25 feet per second and produced a voluminous white smoke. A tear gas cord was made in an identical manner from a 5050 mixture of the smoke formulation and ortho-chlorobenzal malononitrile.

EXAMPLE 2 The procedure of Example 1 was repeated except the amount of zinc oxide in the smoke formulation was reduced to 119 parts by weight. A smoke cord was prepared using Quarrycord as the center thread thereof. The smoke formulation in the cord has a core load of 10.4 grams per foot. The smoke formulation was covered with a 2 mil vinylidene chloride tape and countering rayon threads and fully incased within a polyethylene jacket. The resultant cord has a gross weight of 14.8 grams per foot and an average diameter of 0.278 inch. Upon ignition, the smoke cord produced large volumes of white smoke and burned at a rate of 7.8 feet per second. 7 V

Tear gas cords also were prepared from mixtures of the smoke formulations with 35 percent by weight of ortho-chlorobenzal malononitrite.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

We claim:

1. In a pyrotechnic fume generating cord having substantial flexibility and a length to diameter ratio of at least about 50:1, said cord being adapted to be coiled and spliced and comprising an elongated igniter stem extending along the length of the cord, a fume generating pyrotechnic charge in abutting relationship with said stem along its length and capable of being ignited by said igniter stem and a covering circumscribably confining both said charge and said stem along the length thereof, the combination wherein said pyrotechnic charge is a flameless smoke generating charge, said igniter stem is an. incendiary composition encased within said charge and adapted to progressively burn with a short flame Zone for initiating confined combustion of said flameless smoke generating charge without rupturing said covering and said covering includes a yarn wrapping and an outer plastic sheath exhibiting sufficient structural integrity to provide limited confined flameless combustion of said charge and to promote complete combustion of said charge and. improved smoke generation, said cord having a combustion time of up to about 20 feet per second.

2. The cord of claim 1 wherein the flameless smoke generating charge includes a smoke producing mixture comprising about 10 to 60 percent by weight of a plasticized halogencontaining vinyl polymer and up to 40 percent by weight of zinc oxide.

3. The cord of claim 1 wherein the flameless smoke generating charge is a granular material comprised of plasticized polyvinyl chloride, zinc oxide and perchlorate oxidizer in substantially equal proportions, the charge being capable of flameless smoke generating combustion at temperatures well below l,000 C.

4. The cord of claim 1 wherein the flameless smoke' generating charge includes a smoke producing material comprising about 10 to 60 percent by weight of a plasticized high molecular weight homopolymer of vinyl chloride having an inherent viscosity of about 1.2 and at least 15 percent by weight of zinc oxide, said charge generating large volume of smoke upon ignition and exhibiting flameless combustion at a combustion temperature of about 350500 C.

5. The cord of claim 1 wherein the flameless smoke generating charge comprises about 50 to percent by 9 10 weight of a flameless smoke generating composition prises a metal oxide incendiary mixture and forms a and about 20 to 50 percent by weight of an agent discontinuous core of the cord. persed with the smoke. 8. The cord of claim 1 including a dispersible agent 6. The cord of claim 5 wherein the agent dispersed adapted to be dispersed as part of the flameless smoke with the smoke is a riot control agent. 5 generating charge.

7. The cord of claim 1 wherein the igniter stem com- 

1. In a pyrotechnic fume generating cord having substantial flexibility and a length to diameter ratio of at least about 50: 1, said cord being adapted to be coiled and spliced and comprising an elongated igniter stem extending along the length of the cord, a fume generating pyrotechnic charge in abutting relationship with said stem along its length and capable of being ignited by said igniter stem and a covering circumscribably confining both said charge and said stem along the length thereof, the combination wherein said pyrotechnic charge is a flameless smoke generating charge, said igniter stem is an incendiary composition encased within said charge and adapted to progressively burn with a short flame zone for initiating confined combustion of said flameless smoke generating charge without rupturing said covering and said covering includes a yarn wrapping and an outer plastic sheath exhibiting sufficient structural integrity to provide limited confined flameless combustion of said charge and to promote complete combustion of said charge and improved smoke generation, said cord having a combustion time of up to about 20 feet per second.
 2. The cord of claim 1 wherein the flameless smoke generating charge includes a smoke producing mixture comprising about 10 to 60 percent by weight of a plasticized halogencontaining vinyl polymer and up to 40 percent by weight of zinc oxide.
 3. The cord of claim 1 wherein the flameless smoke generating charge is a granular material comprised of plasticized polyvinyl chloride, zinc oxide and perchlorate oxidizer in substantially equal proportions, the charge being Capable of flameless smoke generating combustion at temperatures well below 1,000* C.
 4. The cord of claim 1 wherein the flameless smoke generating charge includes a smoke producing material comprising about 10 to 60 percent by weight of a plasticized high molecular weight homopolymer of vinyl chloride having an inherent viscosity of about 1.2 and at least 15 percent by weight of zinc oxide, said charge generating large volume of smoke upon ignition and exhibiting flameless combustion at a combustion temperature of about 350*-500* C.
 5. The cord of claim 1 wherein the flameless smoke generating charge comprises about 50 to 80 percent by weight of a flameless smoke generating composition and about 20 to 50 percent by weight of an agent dispersed with the smoke.
 6. The cord of claim 5 wherein the agent dispersed with the smoke is a riot control agent.
 7. The cord of claim 1 wherein the igniter stem comprises a metal oxide incendiary mixture and forms a continuous core of the cord.
 8. The cord of claim 1 including a dispersible agent adapted to be dispersed as part of the flameless smoke generating charge. 